Re: [PATCH] Fix PR71893

[Thomas Schwinge]

Hi!

On Fri, 15 Jul 2016 15:19:59 +0200 (CEST), Richard Biener  
wrote:
> This PR shows that

(There is also PR71901 suspected to be related; David CCed.)

> array_ref_element_size may apply spurious casts which
> in turn end up confusing VN/PRE.
> 
> Fixed as follows, bootstrapped on x86_64-unknown-linux-gnu, testing in
> progress.

Thanks, this resolves PR71893 for nvptx:

>   PR tree-optimization/71893
>   * tree-ssa-pre.c (create_component_ref_by_pieces_1): Compensate
>   for sizetype cast added by array_ref_element_size.
>   * tree-ssa-sccvn.c (copy_reference_ops_from_ref): Likewise.
> 
> Index: gcc/tree-ssa-pre.c
> ===
> *** gcc/tree-ssa-pre.c(revision 238370)
> --- gcc/tree-ssa-pre.c(working copy)
> *** create_component_ref_by_pieces_1 (basic_
> *** 2576,2581 
> --- 2587,2595 
> {
>   genop3 = size_binop (EXACT_DIV_EXPR, genop3,
>size_int (TYPE_ALIGN_UNIT (elmt_type)));
> + /* We may have a useless conversion added by
> +array_ref_element_size via copy_reference_opts_from_ref.  */
> + STRIP_USELESS_TYPE_CONVERSION (genop3);
>   genop3 = find_or_generate_expression (block, genop3, stmts);
>   if (!genop3)
> return NULL_TREE;
> Index: gcc/tree-ssa-sccvn.c
> ===
> *** gcc/tree-ssa-sccvn.c  (revision 238370)
> --- gcc/tree-ssa-sccvn.c  (working copy)
> *** copy_reference_ops_from_ref (tree ref, v
> *** 810,815 
> --- 810,818 
> /* Always record lower bounds and element size.  */
> temp.op1 = array_ref_low_bound (ref);
> temp.op2 = array_ref_element_size (ref);
> +   /* array_ref_element_size forces the result to sizetype
> +  even if that is the same as bitsizetype.  */
> +   STRIP_USELESS_TYPE_CONVERSION (temp.op2);
> if (TREE_CODE (temp.op0) == INTEGER_CST
> && TREE_CODE (temp.op1) == INTEGER_CST
> && TREE_CODE (temp.op2) == INTEGER_CST)


Grüße
 Thomas


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[PATCH] Fix PR71893

[Richard Biener]

This PR shows that array_ref_element_size may apply spurious casts which
in turn end up confusing VN/PRE.

Fixed as follows, bootstrapped on x86_64-unknown-linux-gnu, testing in
progress.

Richard.

2016-07-15  Richard Biener  

PR tree-optimization/71893
* tree-ssa-pre.c (create_component_ref_by_pieces_1): Compensate
for sizetype cast added by array_ref_element_size.
* tree-ssa-sccvn.c (copy_reference_ops_from_ref): Likewise.

Index: gcc/tree-ssa-pre.c
===
*** gcc/tree-ssa-pre.c  (revision 238370)
--- gcc/tree-ssa-pre.c  (working copy)
*** create_component_ref_by_pieces_1 (basic_
*** 2576,2581 
--- 2587,2595 
  {
genop3 = size_binop (EXACT_DIV_EXPR, genop3,
 size_int (TYPE_ALIGN_UNIT (elmt_type)));
+   /* We may have a useless conversion added by
+  array_ref_element_size via copy_reference_opts_from_ref.  */
+   STRIP_USELESS_TYPE_CONVERSION (genop3);
genop3 = find_or_generate_expression (block, genop3, stmts);
if (!genop3)
  return NULL_TREE;
Index: gcc/tree-ssa-sccvn.c
===
*** gcc/tree-ssa-sccvn.c(revision 238370)
--- gcc/tree-ssa-sccvn.c(working copy)
*** copy_reference_ops_from_ref (tree ref, v
*** 810,815 
--- 810,818 
  /* Always record lower bounds and element size.  */
  temp.op1 = array_ref_low_bound (ref);
  temp.op2 = array_ref_element_size (ref);
+ /* array_ref_element_size forces the result to sizetype
+even if that is the same as bitsizetype.  */
+ STRIP_USELESS_TYPE_CONVERSION (temp.op2);
  if (TREE_CODE (temp.op0) == INTEGER_CST
  && TREE_CODE (temp.op1) == INTEGER_CST
  && TREE_CODE (temp.op2) == INTEGER_CST)